Sonoluminescence Is Light Made From Sound

How hard can you punch? Chances are it's nothing compared to the mantis shrimp: its tiny claws strike so fast that the shock wave can actually produce light. This phenomenon is called sonoluminescence, and here's how it works: if an ultrasonic sound wave—that is, one with a frequency far above that of human hearing—hits water, it pushes the water faster than it can react, forcing its pressure to drop suddenly. That leaves behind an area of low pressure in the form of tiny gas bubbles. The process of creating that gas bubble is called cavitation. At this point, it gets really strange: because these cavitation bubbles have much lower pressure than a regular bubble, they immediately collapse, rapidly increasing the pressure inside the bubble. That collapse makes the bubble hotter than the surface of the sun and produces a tiny flash of light. That's sonoluminescence. It's not just the mantis shrimp that makes this happen; things like firing a gun underwater and applying an ultrasonic field can also bring about this effect. Scientists don't yet fully understand why it occurs, but they have a few theories. Explore them in the video below.